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Objective: This study aimed to investigate the effect of breast fibroglandular tissue density on tumor visibility and characterization efficacy in diffusion-weighted magnetic resonance imaging (DWI-MRI).
Methods: After ethics committee approval from Karadeniz Technical University (No: 2025/16, Date: 25.03.2025), 2 independent readers retrospectively evaluated the images of 216 consecutive patients (age range, 16-85 years; mean, 45.5 years) who underwent breast MRI for suspicious clinical-radiological findings and later received a definite diagnosis. Only diffusion-weighted images were used at all stages of evaluation. Evaluation parameters were tumor visibility (4-point scale), malignancy probability (7-point scale), and tumor apparent diffusion coefficient (ADC) value. The most suspicious single index lesion was evaluated for each patient. The malignancy scores were determined by considering the morphologic features and the signal of tumors on the ADC map. The ADC values were measured manually on an MRI workstation. Later on, breast densities determined jointly by the readers using T1-weighted images according to the Breast Imaging Reporting and Data System (BI-RADS) classification. Student’s t-test, Chi-square test, and receiver operating characteristic analysis were used to statistically compare tumor visibility and diagnostic efficacies in different breast density groups (A, B=non-dense, C, D=dense).
Results: Of the 216 patients, 116 (54%) had dense while 100 (46%) had non-dense breast tissue. Around 131 (61%) of the lesions were malignant and 85 (39%) were benign. In 80%-90% of cases with either dense or non-dense breasts, high-moderate tumor visibility was obtained. There was no significant difference between the dense and non-dense breasts in terms of tumor visibility (P ≥ .216) (Table 1). The mean ADC value in malignant tumors was lower than in benign tumors (P < .001). The agreement between the malignancy scores of the readers was moderate (kappa=0.597, P < .001). Diagnostic accuracy values in dense breasts were generally higher than in non-dense breasts (Tables 2 and 3). However, for neither of the evaluation methods nor readers, the result was statistically significant (P ≥ .154).
Conclusion: In dense breasts, the risk of cancer is higher and the diagnostic efficacy of mammography is low. Therefore, additional methods are needed to increase the diagnostic efficacy in malignant tumors. Diffusion MRI is a very popular, highly efficient, easy-to-apply non-contrast-enhanced MR-based molecular imaging method. It has become a standard in routine clinical applications as an adjunct to breast dynamic contrast-enhanced MRI but it is also suitable for standalone use. In conclusion, malignant tumors are highly visible on diffusion MRI and differentiation of malignant from benign tumors can be made with 80%-90% accuracy regardless of breast density. It provides both qualitative and quantitative data. Qualitative data might also be used to grade malignancy probability like in the BI-RADS system. As a result, especially in dense breasts, diffusion MRI might be used in addition to mammography to improve the cancer detection ability.
Cite this article as: Korkmaz HAA, Kul S, Eyüboğlu İ, et al. Effect of breast fibroglandular tissue density in tumor visualization and characterization on diffusion MRI. Current Research in MRI, 2025;4(1):22-26.